In the field of meat processing, such as pork processing, it is well known that excess fat is removed from the back of the loin of an animal carcass to recover the loin before final cutting and/or packing the meat for market. Typically, the carcass of the animal is cut into two halves, and then cut transversely to remove the hind and fore quarters. The resulting portion is commonly referred to as the “middle” and will be referred to herein as the “carcass middle.” Each carcass middle includes a loin to be removed from the fatback. The loin is adjacent to the belly and to the backbone, or chine, and is situated between the ribs and the outer layer of fat.
Various automatic devices have been developed to provide for the separation of the loins from the carcass middle including the devices disclosed in various U.S. Patents owned by the common assignee of the present disclosure including U.S. Pat. Nos. 5,234,371; 5,295,898; 5,407,384; 5,882,252; 6,089,968; 6,547,658; and 7,207,880, the contents of which are incorporated herein by reference in their entireties for teachings regarding the general structure and operation of a “loin puller.”
One of the features described in these patents, particularly the '658 Patent, is a dual blade loin knife assembly which increases the overall yield by separating the belly portion from the loin portion immediately prior to removing the fatback and skin from the loin while reducing the risk of scoring a loin portion of a carcass middle. As described and shown in the '658 Patent, the dual blade loin knife assembly includes a first loin knife referred to as a z-blade and a second loin knife referred to as a j-blade. The z-blade is configured to separate the loin from the belly portion leaving the skin and fatback intact on the loin portion. In order to obviate the need for hand finishing or a separate finishing machine, the j-blade was designed to engage the carcass middle subsequent to the z-blade to remove the skin and a portion of the fatback from the separated loin portion. However, over the years, the animals that these automatic devices process have been genetically changed to become much leaner, and the amount of fatback on the carcass middles has reduced dramatically.
As a result, the j-blade portion of the dual blade knife assembly has become less effective over time because of the lack of fat between the skin and the loin. While the system is designed to “pull out” rather than damage the loin, the lack of fatback often leaves skin remaining on the separated loin portion in order to prevent scoring of the loin. This requires more work on the loin portion at subsequent trim stations. Further, while automated skinning machines have been utilized in processing other meat portions, these devices are used to skin meat portions that have no bones. In other words, they are able to apply top pressure on the product to sufficiently flatten the meat for skinning with a straight blade. However, with respect to pork carcass middles, the separated bone-in loin portion is situated between the ribs and the outer layer of fat making it unable to be laid flat on a skinning station. Thus, anything more than minimal top pressure would result in crushing of the bones resulting in damaged loin portions and ribs.
What is needed therefore is an improved apparatus for separating the belly portion from the loin portion of a carcass middle and for removing the skin and fatback from the separated loin portion having a contoured or “saddled” shape.